A heart is the center of a person's circulatory system. It includes a complex electro-mechanical system performing two major pumping functions. The left portions of the heart, including the left atrium and the left ventricle, draw oxygenated blood from the lungs and pump it to the organs of the body to provide the organs with their metabolic needs for oxygen. The right portions of the heart, including the right atrium and the right ventricle, draw deoxygenated blood from the organs and pump it into the lungs where the blood gets oxygenated. These pumping functions are accomplished by cardiac contractions, i.e., contractions of the myocardium (heart muscles).
Cardiac cells produces the energy required for the cardiac contractions from free fatty acids and glucose via aerobic metabolism. The energy production from glucose is more oxygen efficient than the energy production from fatty acids. In a normal adult heart, about 60-90% of the energy is produced from fatty acid oxidation. If the heart becomes ischemic, blood flow to the heart is reduced, resulting in insufficient oxygen supplying the aerobic metabolism of cardiac cells. In decompensated heart failure, glucose oxidation becomes the primary source of energy produced by the aerobic metabolism. During ischemia and compensated heart failure, fatty acids are still the primary source of energy, even though it is less oxygen-efficient than glucose. In both situations, the heart fails to maintain the normal rate of metabolism because of the reduced availability of oxygen. This results in a reduction of myocardial contractility, and hence, reduction of the heart's pumping efficiency and thus diminished blood flow.
Therefore, as a treatment for ischemia and heart failure, as well as related conditions and symptoms, there is a need to increase the rate of metabolism in cardiac cells in response to the reduced availability of oxygen.